<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>倒计时</title>
    <style type="text/css">
       #canvas{
            position: absolute;
            top:50%; 
            left:50%;
            transform:translate(-50%,-50%);
            border:solid 2px red;
        }
    </style>
</head> 
<body>
    <canvas id='canvas' style="border:solid 1px blue"></canvas>
</body>
<script type="text/javascript" src='./js/digit.js'></script>
<script type="text/javascript" src='./js/clock.js'></script>
</html>